Nanostructure Color Filter for Image Sensor Pixel Miniaturization
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Solution Overview
Problem
The miniaturization of image sensor pixels is hindered by the thickness of optical components such as microlenses and color filters, which limit the formation of small pixels while maintaining necessary light exposure and noise reduction.
Innovation Solution
A method of manufacturing an image sensor using a nanostructure color filter, where a first material layer with a lower refractive index is formed on a sensor substrate, and a nanopattern layer with nanostructures of a higher refractive index is created by bonding a second substrate, reducing its thickness, and patterning to form regions with varying shapes and pitches, allowing for a high-resolution image sensor with reduced thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If traditional microlenses and color filters are used, then light collection and color separation are achieved, but pixel size cannot be reduced due to component thickness limitations
Solution Approach 1:
The patent extracts and eliminates the traditional microlens component from the optical path. Instead of using separate microlens and color filter layers, the invention integrates light guiding functionality directly into the color filter nanostructures, removing the thickness constraint imposed by conventional microlenses and enabling smaller pixel dimensions while maintaining light collection efficiency
Solution Approach 2:
The patent merges the light guiding function (previously performed by microlenses) with the color separation function (performed by color filters) into a single integrated nanostructure color filter layer. This consolidation eliminates the need for multiple thick optical layers, allowing pixel size reduction while preserving both light collection and color filtering capabilities
2Measurement precision
If pixel size is reduced, then resolution is improved, but light exposure and noise reduction become insufficient
Solution Approach 1:
The patent changes the optical parameters of the color filter by using nanostructures with high refractive index materials and optimized geometric configurations. This enables enhanced light transmission and focusing capabilities within the reduced pixel footprint, maintaining sufficient light exposure and signal-to-noise ratio even at smaller pixel sizes for higher resolution
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the production of high-resolution image sensors with smaller pixel sizes by optimizing the refractive index difference and structure of the nanostructures, enhancing light transmission and reflection characteristics, and eliminating the need for traditional microlenses.
Implementation Method 1
The bonding of the first substrate may be performed by an anodic bonding method.
Implementation Method 2
The thickness of the first substrate may be reduced by a chemical mechanical polishing (CMP) method.
Implementation Method 3
Prior to the bonding of the first substrate, the method may further include forming a weak region in the first substrate by implanting ions into the first substrate.
Implementation Method 4
forming a first material layer having a first refractive index on the sensor substrate; and forming a nanopattern layer on the first material layer, the nanopattern layer including a plurality of nanostructures including a material having a second refractive index greater than the first refractive index.
Data Source
AI summary
A method of manufacturing an image sensor includes: preparing a sensor substrate including: a sensor layer including a photosensitive cell; and a signal line layer including lines to receive electric signals from the photosensitive cell; forming a first material layer having a first refractive index on the sensor substrate; and forming a nanopattern layer on the first material layer, the nanopattern layer including a material having a second refractive index different from the first refractive index.